Studies of a 3D PET detector with wavelength shifting fibers

The depth of interaction (DOI) PET detector is one way to achieve high resolution image by determining the depth where most of gamma ray energy is deposited in a scintillator. Because a 2D or 3D profile is obtained for each element, the large amount of data makes the image reconstruction difficult. In this study, we propose a new type of DOI PET detector and estimate a photon yield of a channel and the cost of the materials for manufacturing. An element block of the detector consists of 16 slices of inorganic scintillators, one flat panel PMT, wave length shifting fibers and 256 ch position sensitive (PS) PMT per six element blocks. The main principals of this detector are the condition of total reflection and wave length shifter material. We can see the position where photoelectric effect occurred using the scintillation light not satisfying the condition of total reflection. The photons from the position are transmitted to a channel of PS PMT by wave length shifting fibers. With this detector it is expected to achieve ±1.3 mm resolution for x direction, ±1.5 mm resolution for y and z direction. Ideally we can get the information of the position out of a 50×50×24 mm³ element from only 40 bits signal. Unfortunately we could not perform experimented evaluation owing to delay of delivery of the GSO slices from a company.